Hand-held grinding machine and damping unit and / or counterweight unit

Abstract

The invention relates to a hand-held grinding machine (10a; 10b; 10c), in particular an eccentric or oscillating grinder, having a housing unit (12a; 12b; 12c), a grinding pad (14a; 14b; 14c) for receiving at least one grinding paper (16a; 16b; 16c), an accumulator unit (18a; 18b; 18c), and a damping unit and / or a weight unit (20a; 20b; 20c). The damping unit and / or the weight unit (20a; 20b; 20c) is arranged at least predominantly on the housing unit (12a; 12b; 12c) on the side of the main drive axis (22a) of the grinding pad (14a; 14b; 14c) which is opposite the accumulator unit (18a; 18b; 18c). The invention also relates to a corresponding damping unit and / or weight unit.

Description

TECHNICAL FIELD

[0001] The present application relates to a hand-held grinding machine and a damping unit and / or a counterweight unit. BACKGROUND

[0002] A hand-held grinding machine has been proposed which has a housing unit, a grinding pad for receiving at least one grinding paper and / or at least one grinding sheet and / or at least one grinding web, an accumulator unit, and a damping unit and / or a counterweight unit for damping vibrations occurring in operation. SUMMARY

[0003] The present application proceeds from a hand-held grinding machine, in particular an eccentric grinder or an oscillating grinder, which has a housing unit, a grinding pad for receiving at least one grinding paper and / or at least one grinding sheet and / or at least one grinding web, an accumulator unit, and a damping unit and / or a counterweight unit, in particular for damping vibrations occurring in operation and / or for mass compensation of the mass of the accumulator unit.

[0004] It is proposed that the damping unit and / or the counterweight unit is arranged at least predominantly on the housing unit on the side of the main drive axis of the grinding pad which is opposite the accumulator unit, in particular on and / or between the housing halves of the housing unit.

[0005] By virtue of the configuration according to the application, it is advantageously possible to achieve a vibration-free operation and / or a reliable standing of the hand-held grinding machine. Advantageously, it is possible to attenuate and / or reduce vibration peaks occurring in the vicinity of the grinding pad during operation. Advantageously, user friendliness can be improved.

[0006] The handheld grinder is provided for machining at least one workpiece by a user, in particular for grinding at least one surface of a workpiece. In order to receive the at least one grinding pad and / or the at least one grinding sheet and / or the at least one grinding web by the grinding pad, in particular a Velcro closure connection can be provided. In order to drive the grinding pad, the handheld grinder has a drive motor. In order to cool the drive motor, the handheld grinder has in particular at least one motor fan. The drive motor can in particular be configured as a DC motor, in particular as a brushless DC motor. The energy storage unit is provided for supplying energy, in particular electrical energy, to the drive motor. The energy storage unit comprises at least one, in particular exchangeable, energy storage and at least one receiving element, which is in particular provided for receiving, detachably holding and / or electrically contacting the energy storage. An "energy storage" is in particular to be understood as a unit which receives, stores and releases energy, in particular chemical and / or preferably electrical energy. The energy storage can in particular be configured as an electrochemical capacitor and / or a fuel cell. Preferably, the energy storage is configured as a battery storage, in particular a battery. The energy storage is in particular provided for providing energy, in particular electrical energy, for the drive motor of the handheld grinder. Preferably, the energy storage unit and in particular the receiving element of the energy storage unit is designed for detachably receiving, holding and electrically contacting different types of energy storage. A first energy storage can differ from another energy storage in particular in the storage capacity for electrical energy, in particular the storage capacity for electrical charge, and in mass and / or in size. The grinding pad of the handheld grinder is in particular arranged on an output shaft of an eccentric drive, which is driven by the drive motor, by means of at least one rolling bearing, in particular by means of at least one radial bearing. The eccentric drive has in particular a drive shaft which is rotationally coupled to the drive motor and which is rotatable about a main drive axis. In one operating state, the grinding pad of the handheld grinder can in particular perform an eccentric rotational movement. The drive motor and the eccentric drive form in particular a drive train of the handheld grinder. The handheld grinder has in particular electronic components, in particular control and regulation electronics, for controlling the drive motor. The handheld grinder has in particular at least one on and off switch, which is provided for starting and / or ending at least one operating mode of the handheld grinder. The handheld grinder can also have at least one further switch and / or a regulator, for example a rotational speed regulator, for regulating the rotational speed of the drive motor and / or the grinding pad, and / or at least one user interface, in particular a human-machine interface. The housing unit forms in particular a housing of the handheld grinder. The housing unit is in particular provided for protecting the components of the handheld grinder, in particular the drive motor and the eccentric drive and the electronic components, which are arranged in the housing unit, from external influences, for example dirt and / or dust and / or water. The housing unit forms in particular at least one gripping area, which is provided for handling and gripping the handheld grinder by a user.The at least one gripping region can be configured, in particular, as a so-called palm handle and have, in particular, at least one recess for at least one finger of a user. The housing unit has at least one housing element. Preferably, the housing unit has at least two housing elements which are fastened to one another. The housing elements can be configured, in particular, as housing halves. The housing unit is made, in particular, in a suitable shaping process, preferably in a single-component or multi-component injection-molding process, in particular from plastic, preferably from fiber-reinforced thermoplastic, particularly preferably from glass-fiber-reinforced polyamide. The hand-held grinding machine has, in particular, at least one dust blower which has at least one dust blower housing. The at least one dust blower housing is arranged, in particular, above the grinding pad and is bounded on the upper side by the housing unit. The at least one dust blower is provided, in particular, for removing dust, in particular grinding dust, which is formed during operation of the hand-held grinding machine. The at least one dust blower is configured, in particular, independently of the motor blower of the hand-held grinding machine. "At least a majority" is understood here, in particular, as at least 55%, advantageously at least 65%, preferably at least 75%, particularly preferably at least 85% and particularly advantageously at least 95% of the mass share and / or the volume share. "Provided" is understood, in particular, as specially designed and / or specially equipped. An object provided for a certain function is understood, in particular, as the object fulfilling and / or implementing this certain function in at least one application state and / or operating state.

[0007] The damping unit and / or the counterweight unit of the handheld grinder can be configured, in particular only configured, as a counterweight unit and is provided for a mass compensation of the mass of the accumulator unit and / or for a displacement of the center of mass of the handheld grinder. The counterweight unit in particular comprises at least one buffer mass. The buffer mass of the counterweight unit can be configured, in particular only configured, as a compensation mass for compensating the mass of the accumulator unit and / or for displacing the center of mass of the handheld grinder. The counterweight unit and in particular the buffer mass of the counterweight unit can in particular be fixedly received in the housing unit and / or fixedly connected with the housing unit. The damping unit and / or the counterweight unit can be configured in one piece with the housing unit. Exemplarily, the counterweight unit can be integrally injection-molded in the housing unit by means of a multi-component injection-molding process. The counterweight unit is in particular arranged below the palm grip of the housing unit and in the area below the motor fan, above the dust fan housing and / or laterally. The counterweight unit is in particular not arranged on the grinding pad and in particular not on the drive train and in particular not on the motor fan and in particular not connected with the grinding pad and / or the drive train and / or the motor fan. The counterweight unit is in particular configured differently from the handle of the handheld grinder. The distinction of the counterweight unit from the housing unit is in particular at least in that the material of the buffer mass of the counterweight unit is different from the material of the housing unit. Preferably, the buffer mass of the counterweight unit is made of metal and / or a metal alloy. By means of the damping unit configured as a counterweight unit and / or the counterweight unit, an especially reliable standing of the handheld grinder can advantageously be ensured. In particular, a tipping over of the handheld grinder can advantageously be prevented, which is in particular caused by the gravitational force acting through the mass of the accumulator unit. In particular, a low vertical position of the center of mass of the handheld grinder can be achieved, in particular in the vertical vicinity of the grinding pad.

[0008] It is further proposed that the center of mass of the handheld grinder, measured in particular from the lower edge of the grinding pad, is in the height between 45% and 75% of the overall height of the handheld grinder and at least one straight line, which intersects the grinding pad and is oriented perpendicular to the grinding pad, extends through the center of mass, the minimum distance of said straight line to the outer edge of the grinding pad being in particular between 5% and 25% and preferably between 5% and 15% of the diameter of the grinding pad. Preferably, the center of mass of the handheld grinder, measured in particular from the lower edge of the grinding pad, is in the height in particular between 55% and 65% of the overall height of the handheld grinder. The minimum distance of the straight line through the center of mass, which intersects the grinding pad perpendicularly, is preferably between 2% and 8% and particularly preferably between 3% and 6% of the diameter of the grinding pad. Thereby, a high standing reliability of the handheld grinder can advantageously be achieved. The "diameter of the grinding pad" is in particular to be understood as the diameter of the circular base surface of the smallest imaginary cylinder which just still completely surrounds the grinding pad.

[0009] It is further proposed that the damping unit and / or the counterweight unit comprises at least one buffer mass which is arranged at least predominantly on the side of the main drive axis of the grinding pad which is opposite the accumulator unit. Thereby, a high stand-up reliability of the handheld grinding machine can be advantageously achieved. In particular, a gravitational force acting via the accumulator unit and a resulting displacement of the center of mass of the handheld grinding machine in the direction of the accumulator unit can be advantageously compensated. Furthermore, vibrations occurring during operation of the handheld grinding machine can be advantageously further reduced. The buffer mass is in particular made of at least one metal and / or metal alloy, particularly preferably of an aluminum and / or zinc die cast, in particular by a casting method, preferably by a die casting method. Alternatively or additionally, the buffer mass can also be made of at least one metal and / or metal alloy by a sintering method. The mass of the buffer mass can in particular be adapted to the mass of the accumulator of the accumulator unit. A first buffer mass can in particular have a certain mass and can in particular be provided for operating the handheld grinding machine by means of a first accumulator, while a second buffer mass has a mass which differs from the mass of the first buffer mass and can in particular be provided for operating the handheld grinding machine with a second accumulator. To this end, the buffer mass can be exchangeable. The geometry, in particular a certain geometry having in particular certain dimensions, of the first buffer mass can at least substantially coincide with the geometry, in particular a certain geometry having certain dimensions, of at least one second and / or further buffer mass. Different masses of different kinds of buffer masses having at least substantially coinciding geometries can be achieved by being made of different materials having different densities. The first buffer mass can for example be made of an aluminum die cast for achieving a certain mass, while a further buffer mass can be made of a zinc die cast for achieving a certain further mass, in the case of coinciding dimensions with the first buffer mass. The buffer mass has in particular a density of at least 6 g / cm 3 and preferably a density of between 6.5 g / cm 3 and 8 g / cm 3 . The mass of the first buffer mass can for example be 50 g. The mass of the second buffer mass can for example be 80 g.

[0010] It is further proposed that the vibration of the damping mass in a plurality of spatial directions is enabled by at least one interspace arranged between the housing unit and the damping mass. In particular, the vibration of the damping mass in all six spatial directions is enabled by the interspace arranged between the housing unit and the damping mass. The damping mass can be decoupled from the partial housing unit, in particular in sections. The damping mass can be excited to perform a periodic vibration by the periodic vibration of the housing unit occurring during operation of the handheld grinding machine, in particular a periodic vibration having a frequency in the resonance frequency range of the damping mass. The periodic vibration of the damping mass can be performed, in particular, in a phase offset with respect to the periodic vibration of the housing unit. The phase of the periodic vibration of the damping mass can be offset, in particular, by half a period of the periodic vibration of the housing unit. In particular, the vibration of the housing unit occurring during operation can be reduced and preferably minimized by the periodic counter-vibration of the damping mass. By this configuration, the vibration occurring during operation can be particularly advantageously and easily attenuated and / or reduced. Thereby, a high convenience and / or a high reliability and / or a high user-friendliness can be advantageously achieved. Alternatively, it is conceivable that at least one housing element of the housing unit has at least one recess, wherein the damping mass is connected to said at least one housing element, in particular fixedly, and forms an outer wall, in particular the only outer wall, of said at least one housing element in the region of the recess of the housing element. The flow space within the dust blower housing can be closed by means of at least one sealing lip, in particular gas-tight. The at least one damping element of the damping unit and / or the weight unit can preferably be configured as a sealing lip

[0011] It is further proposed that the damping unit and / or the weight unit comprises at least one damping element, in particular two damping elements, by means of which the damping mass is connected to the housing unit. The at least one damping element can be configured as an elastic element, in particular. By the vibration occurring in the operating state of the handheld grinding machine, the at least one damping element can be excited to an elastic movement and / or deformation, whereby the movement energy of the vibration can be at least partially converted into heat. Thereby, the vibration occurring during operation of the handheld grinding machine can be particularly advantageously and easily attenuated and / or reduced. An "elastic element" is to be understood, in particular, as an element which can repeatedly be macroscopically deformed without the element thereby being mechanically damaged or destroyed, and which element, in particular, autonomously returns to its original state after the deformation. The at least one damping element can be made, in particular, of a synthetic material, preferably an elastomer or silicone and particularly preferably of a thermoplastic elastomer. Thereby, the damping mass can be advantageously connected to the housing unit in a particularly simple technical manner. The at least one damping element preferably has a Shore hardness of between 25 and 80 and particularly preferably a Shore hardness of between 35 and 65.

[0012] It is further proposed that the at least one damping element has at least one inner contour which is connected in a form-locking manner with at least one outer contour of the buffer mass, in particular such that the damping element can be connected to the buffer mass by means of a plug-in connection. An easy connection between the buffer mass and the at least one damping element can thus be advantageously achieved. An especially clear force transmission of the vibrations of the housing unit to the buffer mass can advantageously be made possible for a particularly suitable and effective damping of the vibrations. An especially easy exchange of the buffer mass can advantageously be made possible. Alternatively, it is also conceivable that the at least one damping element is connected to the buffer mass in a material-locking manner, for example by means of an adhesive.

[0013] It is further proposed that the inner contour of the at least one damping element has at least one protrusion, preferably a plurality of protrusions, and / or at least one recess, preferably a plurality of recesses, which abut in the assembled state on the outer contour of the buffer mass. By means of this configuration, vibrations occurring in the operation of the handheld grinder can advantageously be damped. High-frequency vibrations which can occur between the at least one damping element and the buffer mass in the region of the interface in the operation of the handheld grinder can advantageously be reduced in particular. Furthermore, manufacturing-related tolerances of the buffer mass and / or the damping element can advantageously be compensated.

[0014] It is further proposed that the at least one damping element is fastened in a form-locking and / or material-locking manner on the housing unit, in particular by means of at least one injection-molding process. In particular, for a form-locking fastening of the at least one damping element on the housing unit, a special contour, in particular a recess, can be provided in at least one receiving region on at least one housing element of the housing unit, the at least one damping element can have a corresponding contour which matches the special contour of the housing unit. In particular, it is conceivable that at least one catch extends between the at least one damping element and the buffer mass within the housing unit. By means of this, a latching effect can advantageously be produced in the plug-in assembly, whereby a particularly robust and / or stable receiving of the buffer mass on the housing unit of the handheld grinder can be produced. An easy assembly and / or disassembly of the at least one damping element on the housing unit can advantageously be made possible. Alternatively, the at least one damping element can be fastened on the housing unit in a material-locking manner, in particular by means of an injection-molding process, preferably by means of a multi-component injection-molding process. By means of this, the number of work steps for the manufacture of the damping unit and / or the weight unit can advantageously be reduced.

[0015] It is further proposed that the housing unit has at least two housing elements which are fastened to one another in the region of the damping unit and / or the weight unit. The at least two housing elements of the housing unit can be connected in the region of the damping unit and / or the weight unit, in particular by means of at least one connecting element, form- locking and / or force- locking. It is conceivable, for example, that the housing elements form screw seats in the region of the damping unit and / or the weight unit and are fastened to one another by means of a screw connection. By this configuration, an in particular easy assembly of the damping unit and / or the weight unit on the housing unit can advantageously be achieved. An in particular reliable and / or robust arrangement of the damping unit and / or the weight unit on the housing unit can advantageously be achieved. Alternatively or additionally, the at least two housing elements can be fastened to one another in the region of the damping unit and / or the weight unit by means of a material- locking connection, for example by means of an adhesive. Alternatively or additionally, it is further conceivable that the at least two housing elements of the housing unit are fastened to one another in the region facing away from the damping unit and / or the weight unit form- locking and / or force- locking and / or material- locking.

[0016] It is further proposed that the ratio between the maximum distance of the lower edge of the grinding pad to the upper edge of the damping unit and / or the weight unit and the diameter of the grinding pad is at most 0.4. Thereby, the damping function of the damping unit and / or the weight unit can advantageously be improved. In particular, the vibrations of the housing unit in the region of the grinding pad can be particularly effectively reduced. The distance of the upper edge of the damping unit and / or the weight unit to the lower edge of the grinding pad can in particular be minimal. Preferably, the ratio between the maximum distance of the lower edge of the grinding pad to the upper edge of the damping unit and / or the weight unit and the diameter of the grinding pad is between 0.36 and 0.26. Preferably, the minimum distance between the lower edge of the grinding pad and the upper edge of the damping unit and / or the weight unit is 38 mm, particularly preferably 40 mm. Preferably, the maximum distance between the lower edge of the grinding pad and the upper edge of the damping unit and / or the weight unit is 50 mm, particularly preferably 45 mm. The minimum horizontal distance between the outermost edge of the damping mass and the outer edge of the grinding pad is preferably between 2% and 12% of the diameter of the grinding pad and particularly preferably between 5% and 9%. Thereby, the user can advantageously be provided with a good view of the workpiece to be machined when operating the hand-held grinding machine. The nominal diameter of the grinding pad can typically be 125 mm or 150 mm, but it is also conceivable that the grinding pad has a smaller or larger nominal diameter. The value of the actual diameter can in particular differ from the nominal diameter.

[0017] It is further proposed that the buffer mass has at least one crown (Bombierung), which is arranged in particular in the region farthest from the accumulator unit and which extends in particular in the direction of the grinding pad. In particular, the gravitational force acting through the accumulator unit and the resulting displacement of the center of mass of the handheld grinding machine in the direction of the accumulator unit can be advantageously compensated. In particular, the efficiency of the damping vibration can be advantageously increased by the buffer mass. In particular, the contour of the buffer mass can be adapted to the contour of the housing unit. The aesthetics and / or the ergonomics in the gripping area of the handheld grinding machine and / or the handling convenience of the handheld grinding machine can be advantageously improved. The "crown" is in particular to be understood as a bulging deformation. The crown can in particular be configured as a thickening and / or a bending and / or a flexing. The buffer mass can in particular have an asymmetrical shape by means of the at least one crown.

[0018] It is further proposed that the buffer mass is exchangeable. The buffer mass can in particular be of a first kind with a specific first mass and be replaceable and / or exchangeable for a second kind of buffer mass with a specific further mass. The buffer mass can preferably be exchangeable by a user in particular without tools. By such a configuration, the mass of the buffer mass can in particular be adapted to individualized operating situations. The mass of the buffer mass can in particular be advantageously individually adapted to the mass of the accumulator of the accumulator unit, which is in particular exchangeable. Alternatively or additionally, it can be envisaged that the damping function of the damping unit and / or the weight unit can be adapted to operating modes, for example to the rotational speed of the grinding pad and / or to the surface roughness of the workpiece to be machined by means of the handheld grinding machine, by means of the exchange of the buffer mass.

[0019] It is further proposed that the housing unit has at least two mutually parallel housing faces, which support the damping unit and / or the weight unit. The at least two mutually parallel housing faces of the housing unit can in particular support the force action on the damping unit and / or the weight unit in operation, for example due to centrifugal forces. Thereby, the risk of an accidental falling of the damping unit and / or the weight unit, in particular of the buffer mass of the damping unit and / or the weight unit, can advantageously be reduced and in particular minimized, in particular even in the case of strong shaking of the housing unit. A high user friendliness can advantageously be achieved.

[0020] It is further proposed that the center of mass of the buffer mass is between 33% and 42% of the total height of the handheld grinding machine in terms of height, measured from the lower edge of the grinding pad. In particular, the center of mass of the buffer mass can be achieved close to the grinding pad. By such a configuration, a high standing stability of the handheld grinding machine can advantageously be achieved. Vibrations formed in the region of the grinding pad during operation can advantageously be damped particularly effectively.

[0021] The invention also starts from a damping unit and / or a counterweight unit with at least one buffer mass for a handheld grinder.

[0022] It is proposed that the buffer mass is provided for shifting the center of mass and for damping vibrations occurring during operation. With this configuration, the damping unit and / or the counterweight unit for the handheld grinder can fulfill a stabilization function of the handheld grinder in addition to a damping function for damping vibrations occurring during operation of the handheld grinder. A high user friendliness can advantageously be achieved.

[0023] The handheld grinder according to the invention and the damping unit and / or the counterweight unit according to the invention are not limited here to the described applications and embodiments. The handheld grinder according to the invention and the damping unit and / or the counterweight unit according to the invention can in particular have different individual elements, components and units from those mentioned here in order to fulfill the functions described here. Furthermore, in respect of the value ranges given in the disclosure, values within the mentioned boundaries are to be considered as disclosed and can be used arbitrarily. BRIEF DESCRIPTION OF DRAWINGS

[0024] Further advantages can be taken from the following description of the figures. Three embodiments of the invention are shown in the figures. The figures and the description contain a plurality of features which are combined together. The person skilled in the art can suitably consider these features individually and generalize them into other combinations which are meaningful.

[0025] The figures show:

[0026] Figure 1 a schematic view shows a handheld grinder according to the invention with a housing unit, a grinding pad, an accumulator unit and a damping unit and / or a counterweight unit,

[0027] Figure 2 a schematic side view of a handheld grinder is shown,

[0028] Figure 3 a schematic partial view of a housing unit is shown,

[0029] Figure 4a a schematic partial view of a handheld grinder with a cutting line is shown,

[0030] Figure 4b a schematic sectional view of a damping and / or counterweight unit and a housing unit is shown,

[0031] Figure 5a a buffer mass of a damping and / or counterweight unit is shown in a schematic view,

[0032] Figure 5b two damping elements of a damping unit and / or a counterweight unit are shown in a schematic view,

[0033] Figure 5c damping unit and / or counterweight unit with a buffer mass and damping elements,

[0034] Figure 6 shows a further side view of the hand-held grinder,

[0035] Figure 7 shows an alternative configuration of the hand-held grinder according to the application with a housing unit,

[0036] Figure 8 shows a further alternative configuration of the hand-held grinder according to the application. DETAILED DESCRIPTION

[0037] Figure 1 A hand-held grinder 10a is shown. The hand-held grinder 10a is configured as an eccentric grinder. The hand-held grinder 10a has a housing unit 12a, a grinding pad 14a, an energy storage unit 18a and a damping unit and / or counterweight unit 20a. The energy storage unit 18a and the damping unit and / or counterweight unit 20a are arranged on the housing unit 12a. The housing unit 12a forms a gripping area 90a for the manipulation and holding of the hand-held grinder 10a by a user. In the gripping area 90a an on and off switch 80a of the hand-held grinder 10a is arranged. The energy storage unit 18a is provided for the supply of the hand-held grinder 10a with electrical energy. The energy storage unit 18a has a receiving element 74a and an energy storage 76a. The receiving element 74a is provided for the receiving, holding and electrical contacting of the energy storage 76a. The energy storage 76a is configured as a battery. The energy storage 76a is exchangeable (see Figure 6 ). The energy storage 76a is in electrical contact and connection with the energy storage unit 18a via the receiving element 74a. The energy provided by the energy storage 76a supplies a drive motor (not shown) of the hand-held grinder 10a in an operating state. The drive motor drives the grinding pad 14a in an eccentric rotational movement in the operating state via an eccentric drive (not shown). The grinding pad 14a has a circular bottom face. The grinding pad 14a is provided for receiving a grinding paper 16a. The grinding paper 16a is detachably connected with the grinding pad 14a by means of a Velcro closure (not shown). Alternatively, a grinding sheet (not shown) or a grinding net (not shown) can be detachably connected with the grinding pad 14a. The damping unit and / or counterweight unit 20a comprises a buffer mass 40a and two damping elements 44a. The damping unit and / or counterweight unit 20a comprises a region 58a in which the damping unit and / or counterweight unit 20a is arranged on the housing unit 12a. The region 58a is configured as a recess of the housing unit 12a.

[0038] Figure 2A handheld grinder 10a is shown in a schematic side view. The damping unit and / or counterweight unit 20a of the handheld grinder 10a is arranged on the side of the main drive axis 22a of the grinding pad 14a opposite to the accumulator unit 18a. The buffer mass 40a of the damping unit and / or counterweight unit 20a is also arranged on the side of the main drive axis 22a of the grinding pad 14a opposite to the accumulator unit 18a. The handheld grinder 10a has a center of mass 24a. Measured from the lower edge 26a of the grinding pad 14a, the center of mass 24a is located in the range of 45% to 75% of the total height 30a of the handheld grinder 10a measured from the lower edge 26a of the grinding pad 14a in height 28a. The center of mass 24a of the handheld grinder 10a lies on a straight line 32a. The straight line 32a intersects the grinding pad 14a perpendicularly. The minimum spacing 34a between the straight line 32a and the outer edge 36a of the grinding pad 14a is between 1% and 10% of the diameter 38a of the grinding pad 14a. Measured from the lower edge 26a of the grinding pad 14a, the center of mass 70a of the buffer mass 40a is between 33% and 42% of the total height 30a of the handheld grinder 10a in terms of height 72a. The upper edge 60a of the damping unit and / or counterweight unit 20a is arranged with the lower edge 26a of the grinding pad 14a at a maximum spacing 78a. The ratio between the maximum spacing 78a and the diameter 38a of the grinding pad 14a is a maximum of 0.4. The minimum horizontal spacing 84a between the outermost edge 94a of the buffer mass 40a and the outer edge 92a of the grinding pad is between 5% and 9% of the diameter 38a of the grinding pad 14a.

[0039] Figure 3 A housing unit 12a of a handheld grinder 10a is shown. The housing unit 12a has a first housing element 54a and a second housing element 56a. Housing elements 54a and 56a are configured as housing half-shells. Housing elements 54a and 56a are fastened to each other in region 58a of the damping unit and / or counterweight unit 20a (see [reference]). Figure 1 The housing element 54a is fastened to the housing element 56a by means of screws via screw seats arranged in region 58a.

[0040] Figure 4a A portion of a handheld grinder 10a with a damping unit and / or a counterweight unit 20a is shown. Figure 4a The cutting line IV is marked. The cutting line is shown. Figure 4b The cutting direction of the sectional view shown. Cutting line IV extends through the damping unit and / or counterweight unit 20a, housing unit 12a, and grinding pad 14a. From Figure 4bAs can be seen, the buffer mass 40a is connected with the housing unit 12a by means of the damping element 44a. Between the buffer mass 40a and the housing unit 12a a gap 42a is arranged. The gap 42a enables a vibration of the buffer mass 40a in multiple spatial directions.

[0041] In Figure 5a The buffer mass 40a of the damping unit and / or weight unit 20a is shown. The buffer mass 40a has an outer contour 48a. The buffer mass 40a has a convex crown 62a. In the state in which the damping unit and / or weight unit 20a is mounted in the hand-held grinder 10a, the convex crown 62a of the buffer mass 40 of the damping unit and / or weight unit 20a is arranged in a region 64a which is farthest away from the accumulator unit 18a and extends in the direction of the grinding pad 14a (see Figure 1 ). Figure 5b The two damping elements 44a of the damping unit and / or weight unit 20a are shown. The damping elements 44a have an inner contour 46a. The inner contour 46a of the damping elements 44a has a plurality of protrusions 50a and a plurality of recesses 52a. Figure 5c The damping unit and / or weight unit 20a is shown in the mounted state with the buffer mass 40a and the damping elements 44a. The inner contour 46a of the damping elements 44a is in the mounted state in form-locking connection with the outer contour 48a of the buffer mass 40a. The protrusions 50a and the recesses 52a of the inner contour 46a of the damping elements 44a are in the mounted state resting on the outer contour 48a of the buffer mass 40a.

[0042] Figure 6A handheld grinder 10a is shown with a housing unit 12a, a damping unit and / or a weight unit 20a and an accumulator unit 18a. The accumulator unit 18a comprises an accumulator 76a and a further accumulator 88a. The accumulator 76a is detachably connected with the accumulator unit 18a via a receiving element 74a. The accumulator 76a is replaceable and can be replaced by the further accumulator 88a. The further accumulator 88a differs from the accumulator 76a in terms of the electrical storage capacity for supplying the handheld grinder 10a. The further accumulator 88a has a higher charge in the fully charged state than the accumulator 76a. The further accumulator 88a has a higher mass than the accumulator 76a. The damping unit and / or the weight unit 20a has a buffer mass 40a and a second buffer mass 86a. The buffer mass 40a is replaceable and can be replaced by the second buffer mass 86a. The second buffer mass 86a has a higher mass than the buffer mass 40a. The second buffer mass 86a has the same dimensions as the buffer mass 40a and can be connected with the housing unit 12 by means of a damping element 44a. The greater mass of the second buffer mass 86a is achieved by being made of a different material with a higher density than the buffer mass 40a. The second buffer mass 86a is provided for the operation of the handheld grinder 10a in combination with the further accumulator 88a. After the accumulator 76a has been exchanged for the heavier further accumulator 88a, the center of mass 24a of the handheld grinder 10a is shifted in the direction of the accumulator unit 18a. By replacing the buffer mass 40a by the heavier second buffer mass 86a, a partial compensation of the shift of the center of mass 24a can be achieved. A straight line 32a through the center of mass 24a, which intersects the grinding pad 14a perpendicularly, is shifted slightly in the direction of the accumulator unit 18a with respect to the illustration in Figure 2 , but is still spaced apart from the outer edge 36a of the grinding pad 14a by a minimum distance 34a of between 1% and 10% of the diameter 38a of the grinding pad 14a.

[0043] In Figure 7 and 8 further embodiments of the application are shown. The following description and the drawings are essentially limited to the differences between the embodiments, wherein, with regard to components of the same name, in particular with regard to components provided with the same reference numerals, reference can also be made in principle to the drawings and / or the description of the other embodiments, in particular of Figures 1 to 6 . In order to distinguish the embodiments, the letter a is placed after the embodiments of Figures 1 to 6 . In the embodiments of Figure 7 and 8 the letter a is replaced by the letters b and c.

[0044] Figure 7A further embodiment 10b of a hand-held grinder is shown, having a housing unit 12b, an accumulator unit 18b and a damping unit and / or weight unit 20b. The damping unit and / or weight unit 20b has two damping elements 44b. The damping elements 44b are material-locked fastened on the housing unit 12b. The damping elements 44b are material-locked connected with the housing unit 12b by means of an injection-molding process, in particular by means of a multi-component injection-molding process. The damping elements 44b have been injection-molded attached to the housing unit 12b. The first damping element 44b has been injection-molded attached to a first housing element 54b of the housing unit 12b, the second damping element 44b has been injection-molded attached to a second housing element 56b of the housing unit 12b. In assembly, the damping elements 44b connected with the housing elements 54b, 56b can be respectively jacketed onto the buffer mass 40b, so that the buffer mass 40b can be connected with the housing unit 12b.

[0045] Figure 8 A further embodiment of a hand-held grinder 10c is shown. The hand-held grinder 10c is configured as an oscillating grinder. The hand-held grinder 10c has a housing unit 12c, a grinding pad 14c, an accumulator unit 18c and a damping unit and / or weight unit 20c. The grinding pad 14c has a rectangular base surface. The damping unit and / or weight unit 20c has a buffer mass 40c and two damping elements 44c. The buffer mass 40c is connected with the housing unit 12c by means of the damping elements 44c. The housing unit 12c has a first housing surface 66c and a second housing surface 68c. The first housing surface 66c is parallel to the second housing surface 68c. The housing surfaces 66c, 68c support the damping unit and / or weight unit 20c.

Claims

1. Hand-held sander, having - a housing unit, - a sanding pad for receiving at least one sanding paper, - an accumulator unit, and - a damping unit and / or a counterweight unit, characterized in that the damping unit and / or the counterweight unit is arranged at least predominantly on the housing unit on the side of the main drive axis of the sanding pad opposite the accumulator unit, measured from the lower edge of the sanding pad, the center of mass of the hand-held sander is between 45% and 75% of the total height of the hand-held sander in terms of height, and at least one straight line running through the center of mass intersects the sanding pad and is oriented perpendicular to the sanding pad, the straight line having a minimum distance to the outer edge of the sanding pad of between 1% and 10% of the diameter of the sanding pad. The hand-held sander is an eccentric sander or an oscillating sander. The damping unit and / or the counterweight unit comprises at least one buffer mass, which is arranged at least predominantly on the side of the main drive axis of the sanding pad opposite the accumulator unit. The vibration of the buffer mass in multiple spatial directions is enabled by at least one interspace arranged between the housing unit and the buffer mass. The damping unit and / or the counterweight unit comprises at least one damping element, by means of which the buffer mass is connected to the housing unit. The at least one damping element has at least one inner contour, which is connected form-fittingly to at least one outer contour of the buffer mass. The inner contour of the at least one damping element has at least one protrusion and / or at least one recess, which in the assembled state rests on the outer contour of the buffer mass.

2. The hand-held sander as defined in claim 1, characterized in that The at least one damping element is form- and / or material-locked fastened on the housing unit.

3. The hand-held grinder of claim 1 or 2, wherein, The housing unit has at least two housing elements, which in the region of the damping unit and / or the counterweight unit are fastened to one another.

4. The hand-held sander as defined in claim 3, wherein, The ratio between the maximum distance of the lower edge of the sanding pad to the upper edge of the damping unit and / or the counterweight unit and the diameter of the sanding pad is at most 0.

4.

5. The hand-held sander as defined in claim 3, wherein, The buffer mass has at least one crown.

6. The hand-held sander as defined in claim 5, wherein, The buffer mass is replaceable.

7. The hand-held sander as defined in claim 6, wherein, The housing unit has at least two mutually parallel housing faces, which support the damping unit and / or the counterweight unit.

8. The hand-held sander as defined in claim 5, wherein, The center of mass of the buffer mass is between 33% and 42% of the total height of the hand-held sander in terms of height, measured from the lower edge of the sanding pad.

9. The hand-held grinder of claim 1 or 2, wherein, The damping unit and / or the counterweight unit comprises two damping elements.

10. The hand-held grinder of claim 1 or 2, wherein, The at least one damping element is fastened on the housing unit by means of at least one injection-molding process.

11. The hand-held grinder of claim 3, wherein, The crown is arranged in a region furthest from the accumulator unit and extends in the direction of the sanding pad.

12. The hand-held grinder of claim 3, wherein, The buffer mass is provided for the displacement of the center of mass and for the damping of vibrations occurring in operation.

13. The hand-held grinder of claim 1 or 2, wherein, ​ 14. The hand-held grinder of claim 3, wherein, ​ 15. The hand-held grinder of claim 5, wherein, ​ 16. The hand-held grinder of claim 8, wherein, ​ 17. The hand-held grinder of claim 11, wherein, ​ 18. A damping unit and / or a counterweight unit for a hand-held grinding machine according to any one of claims 1 to 17, having at least one buffer mass, characterized in that ​

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